Anytime you drive over a speed bump, pothole, or other rough roads, you will be thankful when the shocks and struts on your car are working well. While these two car components are often discussed together, they are individual components that offer a vital service for keeping your car sturdy and safe. If you’ve ever thought about the difference between shocks and struts, this article should present some light. Let’s take some time to break down what a shock is and a what strut is, the duties they handle, and what occurs when they wear out.
Are Shocks and Struts the Same Component?
Each car driving down the road today has a car suspension system comprised of multiple individual components — including shock absorbers (or struts) and springs. Springs are made to support the car and cushion the ride when the car strikes objects in the road. The shock absorbers (equally known as struts) reduce the vertical travel or motion from the springs along with absorbing or soaking up the impact from road obstructions.
People often use the terms shocks and struts to describe the same component since they actually serve the same purpose. However, there is a difference in the design of the shocks and the strut — and each has unique pros and cons:
- The primary difference between a strut and shock is in the design of the individual suspension system.
- All cars will use a shock or a strut on each of the four corners. Many use struts on the front with a shock absorber in the rear.
- Struts are used on cars without an upper control arm and link to the knuckle while cars with an upper and lower control arm (independent suspension) or a solid axle (on the rear) make use shock absorbers.
What is a Shock Absorber?
A shock absorber is made to be slightly stiffer than a strut. This is mainly since they work with ancillary suspension part to absorb the shock from the road. There are 3 main types of shock absorbers:
- Mono-tube Shock Absorber:The most regular type of shock absorber used is a mono-tube (or gas) shock absorber. This part is made from a steel tube with a rod and piston installed inside. As the car drives over a bump, the piston pushes upward and is compressed slowly by gas for a smoother transition.
- Dual Shock:A dual or twin-tube shock features two vertical tubes that are filled with hydraulic fluid as opposed to gas. As it’s compressed, fluid is sent to the secondary tube.
- Coil-Over Shocks:Cars with shock absorbers mounted on the front are usually called coil over shocks — they have a shock absorber that is ‘covered’ by a coil spring.
What is a Strut?
The most regular type of strut is referred to as the MacPherson strut. This is a very sturdy and durable part that adds the strut and spring into a single unit. There are some cars that utilize a single strut with a separate coil spring. Struts are typically installed to a steering knuckle, with the top of the ‘spring’ installed to support the body. Struts are much smaller than shock absorbers, which is a primary reason why they are often used in cars with compressed suspension travel.
Should I Use a Shock or Strut in My Car?
Like any other moving component, a shock and strut are made to wear out over time. Depending on the type of car you own, they can last anywhere from 30,000 to 75,000 miles. They should be changed as recommended by the car manufacturer, and it’s always a good idea to use OEM (original equipment manufacturer) replacement parts when they need replacement. If your vehicle came from the factory with shock absorbers, you have to change them with the same type of component. The same is to be said about struts.
Shocks and struts should equally be changed in pairs (on the same axle at the least) and the car should have a professional suspension alignment finished to ensure the tires, steering, and complete suspension system is aligned properly.